JPS60194035A - Corrosion resistant copper alloy - Google Patents

Abstract

PURPOSE:To manufacture a Cu alloy having superior resistance to corrosion, especially dezincification corrosion and superior machinability at a low cost by adding specified amounts of Zn, Sn, Pb, Fe, Ni, Sb and P to Cu. CONSTITUTION:This Cu alloy consists of, by weight, 63.0-66.0% Cu, 0.7-1.2% Sn, 1.0-2.5% Pb, 0.1-1.0% Fe, 0.1-0.7% Ni, 0.01-0.1% Sb, 0.01-0.2% P and the balance Zn. The alloy has superior resistance to dezincification corrosion and superior machinability, and the structure is practically an alpha-phase structure. The alloy is suitable for use as a material for a valve, machine parts, ship parts, electric parts, a pump shaft, bushing, a pipe, a plate, etc. in numerous uses.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a copper-based alloy with improved corrosion resistance, particularly dezincification corrosion resistance, and improved machinability.

Free-cutting brass rods, forging brass rods, naval brass rods, high-strength brass rods, and the like have been widely used as wrought materials of copper-based alloys. However, none of these copper-based alloys is satisfactory as a material having both corrosion resistance and machinability properties. In other words, free-cutting brass rods, brass rods for forging, etc.
Due to the high content of zinc, it has the disadvantage that zinc corrosion easily occurs in hot water, contaminated water, and seawater. Furthermore, naval brass rods and high-strength brass rods, which are said to have good corrosion resistance, have the drawbacks of poor machinability and insufficient dezincification corrosion resistance.

On the other hand, in order to improve the dezincification corrosion resistance of this type of copper-based alloy, a copper-based metal (Japanese Patent Laid-Open No. 55-97443) in which a small amount of phosphorus was added to a brass rod for forging (?l5C3771) was developed.
) and copper-based alloys (Special Publication No. 51-203
No. 75) etc. have been developed. The former method aims to increase the α-phase structure by adding a small amount of phosphorus, thereby suppressing dezincification corrosion, but adding phosphorus alone does not provide sufficient dezincification corrosion resistance. It is difficult to obtain, and various problems arise in practice.

In addition, the latter copper-based alloy aims to improve dezincification corrosion resistance by the contribution of tin and nickel, but since the amount of tin added is relatively high at 12 to 20% by weight, the appearance of the Cu4Sn phase This has the disadvantage of being made into a single company, which tends to cause cracks in the forging process, and it is difficult to stabilize the structure because the particles tend to segregate.As a result, the control of the heat treatment process has become complicated, and the corrosion resistance of the alloy has deteriorated. It has a major drawback in that it tends to cause variations.

The purpose of the present invention is to solve the above-mentioned problems with conventional heir-based alloys of this type. The object of the present invention is to provide a copper base metal that is easy to manage, always provides stable corrosion resistance, and can be manufactured at low cost.

The copper-based alloy according to the present invention is copper 630-660, Shigeya Kotin 07
~12% by weight, lead lO~2.5% by weight, iron 0.1-1.
0% by weight, nickel 0.1-07% by weight, antimony 0
．． 0.01 to 0.1% by weight, 0.01 to 0.2% by weight of phosphorus, and the balance is zinc and accompanying impurities, and has a basic structure of substantially α-phase structure.

In addition, the copper-based alloy according to the present invention has the following characteristics: (1) The structure is an alpha phase strengthened by the synergistic effect of tin and nickel and additives, so it has excellent corrosion resistance, especially dezincification corrosion resistance, and (2) can be used as a return material for bronze castings, ■
It has many excellent characteristics, such as excellent mechanical properties such as machinability, and ■ Easy control of heat treatment in the manufacturing process, which allows you to always obtain products of stable quality. Some 0 Hereinafter, the effect of adding each element in the copper-based alloy according to the present invention and the reason for limiting the composition range will be explained.

Copper (63.0 to 660% by weight) The α phase increases in brass when the copper content is about 62% or more. On the other hand, if too much copper is added, the corrosion resistance will improve, but the tensile strength and hardness will decrease. The amount of copper was limited to 630 to 66.0% by weight considering the fact that dezincification corrosion mainly occurs from the β phase and economic efficiency.

Tin (07-12% by weight) Tin is added to improve corrosion resistance. Said Special Public Service 1977
In the copper-based alloy No. 2037, the amount of tin is 12 to 20% by weight.
However, as a result of subsequent research, it was found that even if the amount of tin added was reduced, better corrosion resistance could be obtained in combination with the improvement in corrosion resistance due to nickel, antimony, and phosphorus, which will be described later. In addition, in order to improve corrosion resistance, 07 Shigetoshi%
It is necessary to add less than t of tin.

Lead (10 to 25% by weight) Lead is added to improve machinability, but if it is added more than 1.0% by weight, sufficient machinability cannot be obtained, and if it is added above 25% by weight, As a result, tensile strength, elongation, impact value, etc. decrease.

Iron (0.1 to 1.0% by weight) Iron has the effect of refining the crystals of the alloy, but if it is too small, the effect is small, and if it is added more than 1.0% by weight, the corrosion resistance will deteriorate and the mechanical Since the elongation of properties and impact per shift are reduced, it is necessary to keep the content in the range of 0.01 to 1.0% by weight.

Nickel (0.1-0.7% by weight) Nickel provides increased corrosion resistance through a synergistic effect with the field and also improves its mechanical properties.

Since nickel has a negative zinc equivalent, the α phase increases, and adding nickel prevents the increase in the β phase and suppresses the generation of the r phase, making it possible to create an alloy with high strength and toughness. can. Therefore, corrosion resistance and mechanical properties can be improved by adding nickel, and the amount of addition is o.
, io. A range of 7% by weight is preferred.

Antimony (001-0.1% by weight) Antimony is added to improve corrosion resistance.

Combined with the aforementioned tin, the tendency for dezincification corrosion is suppressed.

If the amount of tin added is less than 0.01% by weight, the effect will be small, and if it is added more than 0.01% by weight, it will become hard and dangerous.

Phosphorus (Q, O1 to 0.2% by weight) Phosphorus is added to improve corrosion resistance by coexisting with antimony. Phosphorus alone does not have a significant effect on improving corrosion resistance, but its effect increases when it coexists with antimony. If the weight is less than 0.001% by weight, there will be little effect on improving corrosion resistance, and if it is more than 0.2% by weight, cracks may occur depending on the degree of processing.

In addition, impurities that may be contained in the copper-based alloy according to the present invention include aluminum, manganese, silicon, sulfur, etc., and the total amount is 0.5% by weight or less. This can be achieved by appropriately combining the following elements within their allowable ranges, and a copper-based alloy with excellent corrosion resistance, machinability, and mechanical properties can be obtained. In addition, the copper-based alloy according to the present invention has excellent corrosion resistance against hot water, contaminated water, seawater, etc., and also has high cerebrospinal fluid removal properties, so it can be used in valve parts (stem disks, etc.), mechanical parts, etc.
It has many uses in marine parts, electrical parts, shafts, pump shafts, bushes, pipes, plates, etc.

Hereinafter, the effectiveness of the copper-based alloy according to the present invention will be clarified through Examples.

Table 1 shows the chemical components of the copper-based alloy according to the present invention and the copper-based alloy for comparative samples, and Table 2 shows the chemical composition of the copper-based alloy according to the present invention and the copper-based alloy for comparison samples.
The table shows the tensile strength, elongation, hardness, and drill test field of each sample of copper base metal.

In Table 1, the data! 1 is JIS standard forging brass rod (C-3771), Warabi 2 is JIS standard naval brass rod (C-4641), A 3 C, JIS jlA grade high strength brass rod (C-6782), 4 is Special Public Service 51-2
Corrosion-resistant copper-based alloy according to No. 0375, lees 5 and shoe 6! 7 is a copper-based alloy according to the present invention, and 8 is JP-A-55-97443.
This is a copper-based alloy according to No.

As is clear from the mechanical property test results shown in Table 2, the corrosion-resistant copper base metal according to the present invention contains relatively large amounts of elements that reduce elongation, such as tin, lead, and iron. It is elongated despite the fact that it is made of aluminum, and since it contains lead, it has extremely good machinability.

On the other hand, Table 3 shows the results of the dezincification corrosion test for each of the samples, which were conducted using the dezincification corrosion test method specified in 15O6509. That is, the sample was embedded in phenolic resin so that the rough surface of the sample was perpendicular to the extrusion direction, the sample surface was polished to No. 1200 and then puff finished, and then the sample was chlorinated at 12.7 t/l. Immersed in an aqueous solution of product salt (CuCA2-2H20),
After being held at ℃ for 24 hours, the samples were taken out and the average dezincification corrosion depth was measured.

As can be seen from the results of the dezincification corrosion test of No. 3, the copper-based alloys according to the present invention (Ishi 5, Ii 6, Hue 7) have a significantly small dezincification corrosion depth. It has good corrosion resistance even when compared to No. 1), and has significantly better dezincification corrosion resistance than other comparative materials.

In addition, since the corrosion-resistant copper base metal according to the present invention has a relatively small amount of tin, field failure and the like will not occur, and as a result, corrosion resistance etc. will not vary greatly due to slight differences in heat treatment conditions. It becomes easier to manage the heat treatment process, and there are virtually no variations in resistance.

As mentioned above, the present invention has excellent practical utility.

[Brief explanation of drawings]

Figure 1, Figure 2, negative) Figure 3, Figure 4, and Figure 8 are micrographs of Mu copper-based alloy samples subjected to dezincification corrosion tests. Figure 2 shows the two types of brass rods for producing d, iu.
Figure 3 shows sample A of sC4641 Naval Brass Rod (2 types).
Figure 4 shows sample layer 4 (Japanese Patent Publication No. 51-20375), and Figure 8 shows sample layer 8 (Japanese Patent Publication No. 55-9744.3). Each microscope is available. FIGS. 5, 6, and 7 are micrographs of copper-based alloy samples according to the present invention that were subjected to dezincification corrosion tests; FIG. 5 is sample 5, and FIG. 6 is sample f; 6 and 7 are microscopic photographs of samples 7 and 7. (A is the corrosion depth of 50 parts) Patent applicant: Toyo Halve Co., Ltd. Figure 1 Figure 2 Figure 3 Figure 4 Continued from page 1 0 Inventor Tatsu Mamoru Inukai Suwa City Kogandori Factory

Claims (1)

[Claims] @ 63.0-660% by weight, tin 0.7-12% by weight,
Lead 10-25% by weight, iron 01-10% by weight, nickel 0
1 to 0.7% by weight, antimony 0.01 to 01% by weight,
A corrosion-resistant copper-based metal having excellent machinability and having a substantially α-phase structure consisting of 0.01 to 0.2% by weight of phosphorus and the balance being zinc and accompanying impurities.